It seems like they might display charts before they are valid.
I have wondered how firms like this, who publish electronic updates, deal with the issue with information becoming valid at Date X, when the customer will be updating every month on date Y.
It is a fact that historically (not sure what they do now) Jeppview's approach plate database stored only the one set of charts. If a chart became authorised on a date which does not coincide with the date on which the new database becomes available for download (which is virtually certain) then the only safe way to deal with that is to not include it until the next update.
However recently I heard that Jepp changed this, and you now run two copies of their database on your client device. As with a proper IFR GPS, the database changes over at midnight on the correct date, automatically - though presumably not if you are airborne at the time!
Jepp have always offered both versions of the chart if it became effective during a cycle. JeppView even offers printing the differences.
Until the last version, JeppFD on the iPad only supported the most recent chart. With the last update they have changed it to offer both versions and show which one is the current one. Apparently they introduced a bug there, no big deal. There will probably be an update soon...
Did JV3 offer two databases?
I have seen that in JV4 - the PC product - but not in JeppTC on the IPad.
Two databases means a few GB extra storage.
Yes, it's a feature of JV4. JV3 has been obsolete for a few years. JeppTC has also been superseded by JeppFD and is only kept for compatibility (some operators have approvals for it).
It's one of the features that is still much better in the Windows JeppView -- I can get a detailed list of what has changed about a specific airport, down to each plate which then has a change log at the bottom.
Is the JV4 change log any more comprehensive than the "Changes" text printed on the side of the approach plate? Usually the latter is really brief, or useless (e.g. "redrawn").
